1. Field of the Invention
This invention relates to structure for supporting a surgical instrument, such as an endoscope, and more particularly to such structure which provides for repositioning of the instrument during surgery without stressing an incision through which the instrument extends.
2. Related Art
Laparoscopic surgery is a procedure in which surgical instruments and a viewing scope, referred to generally as an endoscope and more specifically as a laparoscope, are inserted through respective small puncture wounds or incisions into the abdominal cavity of a patient. A small video camera is attached to the laparoscope and connected to a television monitor for viewing the procedure.
The instruments and the laparoscope are inserted through cannulae which are first inserted through the incisions. Cannulae are hollow tubes with gas valves. The cannulae are left in the puncture wounds throughout the procedure. This allows the instruments and scope to be removed and reinserted as necessary.
To aid in visualizing the intraabdominal structures, gas is inserted through one of the cannulae to raise the abdominal wall. Seals are required at the exit points of the scope and instruments to prevent the gas from escaping.
The viewing laparoscope is inserted through a cannula which is usually inserted through an incision made in the umbilicus. The scope is then directed toward the pelvis for pelvic surgery or toward the liver for gallbladder surgery.
Throughout the procedure it is necessary for the surgeon, assistant surgeon, or a scrub nurse to hold the scope and direct it at the target of the surgery. It is constantly being repositioned to obtain the best view. This process ties up one hand of the surgeon or assistant surgeon, if either holds the scope. The scrub nurses also have other tasks to perform, and holding the scope interferes with performing these tasks. It is also difficult for the surgeon to direct others to position the scope for the best view. When the scope is not held by the surgeon, it is often misdirected.
The support of a laparoscope has been provided through the use of robotic retractors. Retractors hold instruments in fixed positions, such as for holding an incision open to allow a surgeon access to the underlying body parts. The retractors are fixedly clamped to a mechanical skeleton. This skeleton has also been used to hold a laparoscope in a fixed position. When it is desired to move the scope, the clamp must be readjusted, and also the skeleton linkages must usually also be adjusted to accommodate a change in angle of insertion of the laparoscope.
An apparatus that accommodates changes more readily is a robot-like arm having ball joints next to an instrument holder. This apparatus is sold under the proprietary name The Leonard Arm by Leonard Medical, Inc. of Huntingdon Valley, Penn., and is described in U.S. Pat. No. 4,863,133 issued to Bonnell. Two articulating arms are used to couple an instrument clamp to the operating table rail. A vacuum supply is used to frictionally hold the joints. Three joints provide three degrees of freedom of movement. When not freely moveable, manual force on the instrument clamp is sufficient to reposition the instrument.
The invention of Bonnell is intended as a general-purpose instrument holding apparatus. As such it is up to the user to control movement of the instrument supported on the apparatus, since the axes of movement are independent of and spaced from the patient, except for ball joints next to the instrument holder. Further, this apparatus presents two arms that extend upwardly over the operating table which interfere with access to the patient by attendants, and requires a dedicated vacuum source in the operating room.
A less imposing and more technically sophisticated robotic arm that is commercially available is sold under the name AESOP by Computer Motion, Inc. of Goleta, Calif. This arm has servo-operated joints with computer-controlled motion based on a multipedal foot-operated input device. This device has articulation about axes that are also spaced from the endoscope, thereby requiring very careful movement control by the surgeon in order to avoid stressing the tissue adjacent the laparoscope incision. Further, the computer used to control movement makes the system very expensive to produce.
A less expensive manual apparatus is described in U.S. Pat. No. 4,573,452 issued to Greenberg. A rigid metal ring that surrounds the incision area is mounted above the table. A vertical control arm is mounted on a ball-and-socket joint along the metal ring. A tensionable cable-like component connects the top of the control arm to a laparoscope holder. After initial placement of the holder, the cable-like component is secured, after which movement of the laparoscope is achieved by pivoting the control arm about the ball and socket joint. It is suggested that the ball and socket joint be coplanar with the incision through which the laparoscope extends.
The Greenberg apparatus requires the use of the ring which is positioned over the patient. This ring, though of low profile can interfere with surgical procedures. Further, the laparoscope is pivoted about the ball-and-socket joint which is located along the ring. Thus, except for movement of the scope about the axis that intersects both the incision and joint, the laparoscope moves from the incision, causing stress on the tissue around the incision. Significant changes in position of the scope requires release and repositioning of the cable-like component.